Field
The present invention relates to novolac vinyl esters useful as thermal resistance conferring components for anaerobic curable compositions, and anaerobic curable compositions having such novolac vinyl esters. The compositions are particularly useful as adhesives and sealants.
Brief Description of Related Technology
Anaerobic adhesive compositions generally are well-known. See e.g. R. D. Rich, “Anaerobic Adhesives” in Handbook of Adhesive Technology, 29, 467-79, A. Pizzi and K. L. Mittal, eds., Marcel Dekker, Inc., New York (1994), and references cited therein. Their uses are legion and new applications continue to be developed.
Conventional anaerobic adhesive compositions ordinarily include a free-radically polymerizable acrylate ester monomer, together with a peroxy initiator and an inhibitor component. Oftentimes, such anaerobic adhesive compositions also contain accelerator components to increase the speed with which the composition cures.
Conventional anaerobic adhesive compositions have also been conferred improved thermal properties thereupon. For instance, U.S. Pat. No. 3,988,299 (Malofsky) refers to a heat curable composition having improved thermal properties, which includes certain acrylate monomers and maleimide compounds.
L. J. Baccei and B. M. Malofsky, “Anaerobic Adhesives Containing Maleimides Having Improved Thermal Resistance” in Adhesive Chemicals, 589-601, L-H Lee, ed., Plenum Publishing Corp. (1984) report the use of maleimides—specifically, N-phenyl maleimide, m-phenylene dimaleimide and a reaction product of methylene dianiline and methylene dianiline bismaleimide—to increase the thermal resistance of anaerobic adhesives which are fully cured at temperatures of at least 150° C.
U.S. Pat. No. 6,043,327 (Attarwala) speaks to one-part, anaerobic adhesive compositions, capable of curing under ambient temperature conditions reaction products of which exhibit resistance to thermal degradation at elevated temperatures. These compositions are comprised of (a) an acrylate component; (b) a coreactant component of a specified structure, examples of which include triallyl cyanurate, triallyl trimesate, and triallyl isocyanurate; (c) a maleimide component; and (d) an anaerobic cure-inducing composition.
Notwithstanding the state of the technology, it would be desirable to provide additional choices to the end user when it comes to anaerobic curable compositions for use in high temperature environments.